Rumble is a mail server suite for SMTP (ESMTPSA), HTTP, POP3 and IMAP4v1 with an extensive C/C++ and Lua API for scripting. It comes with support for SSL/TLS, SQLite and MySQL and has a web-based administration and webmail feature. Additional included modules feature greylisting, DNS blacklisting, SpamAssassin support and dynamic performance scaling as well as a multithreaded structure that allows for clustering of multiple servers for one or all domains, and with the ease of the Lua API, you can create your own new server mailing lists, CRM software, e-marketing and other extensions within minutes.

Geppetto is a remote system automation for restricted environment with an easy to use web interface. Especially useful for a park of machines behind an ADSL box/router (floating IP / no incoming connection allowed). Only HTTP(s) used.

AOEmu is a high performance server emulator for the sci-fi MMORPG Anarchy-Online. This project aims to provide a fully functional server system for running and maintaining an Anarchy-Online server over one or many server machines running Linux.

OpenSAN is a free software project realizing Storage Area Network system. This is small firmware that turns server (having at least one hard drive) into an iSCSI target accessible through the Ethernet interface.